Well 700mg is extremely high for me personally I only need 120-200 MG that lasts me about 5-6 hours and i take a melatonin for sleep or do some exercise which helps alot. But each person is different sounds like you need a sabbatical so lower dosages help you
Melatonin helps me sleep the first four or so hours, then Zyrtec helps with the last four. You can take the Zyrtec any time since it's a 24 hrs pill, but I try to take mine around bedtime. They don't make me groggy or anything during the day, and they even help with mosquito bites!
Edit: Also Costco sells a year's supply for the cost everyone else sells a month's worth.
Melatonin only helps me sleep within a 45 minute windows which can be ignored. Zyrtec does nothing to me only benadryl and alcohol. Have a sleepy effect for me.